1. Field of the Invention
This invention relates to an inkjet printer, and more particularly, in an inkjet printer that is provided with a plurality of micro injecting devices, to a printer that prevents drying of nozzles of the micro injecting devices that are not in use during printing and to a control method of the same.
2. Prior art
Generally, a micro injecting device is designed to apply electric and thermal energy of a certain magnitude to the object and induce volume change in the object to thereby enable adequate supply of the item of a very small amount to the intended object, such as supplying ink, injection fluid, gasoline and the like to certain objects such as paper, human bodies and automobiles.
Recently, with the aid of development in electric and electronic technology, these micro injecting devices are also being developed at a faster rate, and are being applied to a wide range of application of everyday life. An example of the application of micro injecting devices in everyday life would be an inkjet printer.
Unlike the existing dot matrix printer, an inkjet printer that utilizes micro injecting devices has many advantages that include being able to portray various colors according to the use of the micro injecting devices, a lower noise level and a higher printing quality, and for those reasons the use range thereof is tending to increase.
Generally, the size of an inkjet printer is determined by the dimensions of the paper being used, and electronic control of the precise mechanical mechanisms and the semiconductor chip circuit is required for paper insertion, paper advance and reverse, and paper supply. However, the printing portion is simply made up of the micro injecting devices that are provided with an ink container and nozzles, along with the paper which is fed to the nozzles at a 0.4-0.7 mm spacing.
The water based ink contained in the ink container flows into a small chamber within the nozzle, and when an electric signal is applied to a piezo element or thermal element, the ink expands due to pressure/heat and is linearly sprayed and printed, and the printer controller moves the micro injecting devices formed of a nozzle assembly to the next position. The nozzle assembly usually includes 32-64 parallel arranged nozzles that have a diameter of 40-60 xcexcm, respectively. That is, the micro injecting device includes nozzles that pass ink through and a spraying means that spray ink to the outside through the nozzles.
The inkjet printer which creates a picture by spraying water based ink through the nozzles, is classified according to the way in which the ink is sprayed, roughly by the thermal method printer and the piezo aqueous method printer.
The thermal method is a method in which the ink is instantly heated to a high temperature of 200-300xc2x0 C. and then sprayed, where air bubbles are generated by instant heating caused from an electric signal that is applied to the resistor of the micro injecting device. Through the force of these air bubbles, the ink is pushed out of the nozzles that compose the micro injecting device and is printed on paper.
On the other hand, in the piezo aqueous method, when an electric impulse is applied to the piezo element in the micro injecting device, the element vibrates, and as a consequence of this vibration, the ink exits the nozzles of the micro injecting device and prints on the paper. The micro injecting device initially absorbs the ink poured into an ink cartridge and then the ink is supplied by surface tension, capillary effect and impulse of the absorbed ink.
As depicted in FIG. 1, for printing operations, the color inkjet printer performs color printing by placing two micro injecting devices, namely, a micro injecting device 4a for black and white printing and a micro injecting device 4b for color printing, on to a carriage 3, coupling the carriage 3 on to a timing belt 2 which is connected to a motor 1, and spraying ink on to paper (a) through nozzles of the color or black/white micro injecting device according to the methods mentioned above while reciprocating the devices side to side along a guide shaft 6.
Generally, in inkjet printers which use two micro injecting devices for printing, one micro injecting device does not print while the other micro injecting device is being used to print.
For example, while printing is being performed on paper (10) by spraying black ink through the use of the black micro injecting device 4a, the color micro injecting device 4b is not used and is exposed to the ambient air.
Thus, in case the unused micro injecting device is left exposed to air for a long time, a problem arises when the nozzles of the micro injecting device become dry.
To prevent this, while one micro injecting device is printing and the other micro injecting device is left unused and exposed to the air for a certain amount of time, the method of temporarily stopping the printing operation and moving the unused micro injecting device to a maintenance location 7 and spraying a certain amount of ink was used.
However, the above method increased ink consumption due to needless ink spraying and slowed down print data printing speed due to movements that have no connections to the actual printing during the print data printing operation.
In addition, the maintenance location is generally installed with many structures having technical collision characteristics and this causes the problem of noise.
Therefore, the present invention has been made to overcome the above conventional problems, and it is an object of the present invention to prevent drying of the nozzles without moving the unused micro injecting device to a maintenance location and spraying a small amount of ink during printing.
The above object is accomplished by a printer capable of preventing drying of nozzle according to one aspect of the present invention, including a plurality of micro injecting devices provided with a plurality of nozzles that receive nozzle drive data to drive the nozzles and spray ink; a plurality of micro injecting device drivers that provide the nozzle drive data for controlling the spraying of the nozzles and making the ink inside the nozzles move up and down; a carriage that is mounted with the plurality of micro injecting devices and reciprocates side to side above the paper; a control section that drives the unused micro injecting device among the plurality of micro injecting devices to make the ink move up and down.
Preferably, the control section drives the unused micro injecting device in the acceleration and deceleration regions of the carriage to make ink move up and down.
Preferably, the plurality of micro injecting devices consist of a color micro injecting device for color printing and a black and white micro injecting device for black and white printing.
The above object is also accomplished by a nozzle drying preventing method according to another aspect of the present invention, for a printer provided with a plurality of micro injecting devices mounted on a carriage and which reciprocate side to side above the surface of paper, including the steps of driving the corresponding micro injecting device when a print command is generated, driving the unused micro injecting devices among the plurality of micro injecting devices and making the ink move up and down.
Preferably, the step of driving the unused micro injecting device drives the unused micro injecting devices in the acceleration and deceleration regions of the carriage to make ink move up and down.
Preferably, the plurality of micro injecting devices consist of a color micro injecting device for color printing and a black and white micro injecting device for black and white printing.